Trafo Power Solutions, located in Johannesburg, designed and provided dry-type transformers for Kyrgyzstan's gold mine expansion project. This is one of its latest achievements. The custom engineered unit of the project will operate at an altitude of 4,020 meters at an altitude of -40⁰C. The company provided a 3,000 kVA transformer with 6.3 kV primary and 400 V secondary specifications.

“In terms of cooling, altitude alone presents a special challenge to the design,” said David Claassen, Managing Director of Trafo Power Solutions. "Most large electrical equipment has a rating of 1,000 m or less, so we had to lower the equipment’s rating to take into account the altitude. The higher the location, the lower the cooling efficiency-the temperature range on site is -40°C to Between 25⁰C."

The 8 ton outdoor transformer has a specially designed housing to prevent snow, dust and humidity, while also dissipating heat. Claassen points out that there is a risk of condensation when shutting down the transformer under these conditions. "Therefore, we built a control system in the design to automatically heat the housing when the transformer stops running for any reason," he said. "Of course, once the transformer returns to operation, the heater will turn off again."

Under harsh environmental conditions, the shell is coated with a corrosion-resistant C5 paint scheme. The design also includes a neutral grounding resistor with special surge protection components. He emphasized that Trafo Power Solution's strategic partner TMC Transformers-a leading manufacturer based in Italy-has extensive experience in producing transformers for these harsh conditions.

"Dry-type transformers are very suitable for these cold conditions because there is no fluid involved in the cooling process, and it is fairly simple to provide the necessary heating and cooling as needed," he said. "Almost no maintenance is required, which is a big advantage in remote areas like this."

Due to travel restrictions due to the COVID-19 pandemic, customers can remotely witness factory acceptance tests conducted at TMC IEC approved factories in Italy, which allows all routine and special tests to be done in-house. "Online factory acceptance testing uses communication technology and cameras around the test bench, including cameras for technicians who are focused on performing the test," Claassen said. "This allows the customer to check all aspects of the specification in detail and freely interact with the TMC and Trafo Power Solutions teams during the witness test."

At the beginning of the project, Trafo Power Solutions will provide customers with published tolerance theory test reports-in terms of loss and impedance-IEC expectations. He then compared these readings with the actual readings obtained during the factory acceptance test, and he said the results remained unchanged within the IEC requirements.

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